How do I restore my HP G56 running windows7 to factory settings or get a new os product key?

I can no longer install windows updates because the computer itself claims I do not have a genuine copy of windows 7. The laptop was purchased with all software installed from HP. The exact error is "Windows 7 build 7601 This is not a genuine copy of windows"

Do I need to restore my computer to factory default or do I just need a new product key?